Electromagnetic talking machine



Oct. 27, 1936. s, BEGUM 2,058,399-

ELECTROMAGNETIC TALKING M1CHINE 1 Filed June 6, 1935 Patented Oct. 27,.1936

v UNITED STATES ELECTROMAGNETIC TALKING MACHINE Semi Begun, Berlin,Germany, assignor to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof,

Germany Application June 6, '1935, Serial No. 25,354 In Germany June 9,1934 3 Claims. (01. 179-1002) The invention relates to electromagneticsound recording and reproducing machines and more particularly to theso-called talking heads thereof in which electromagnets are arranged-tocoact with a steel wire or tape as a sound record- I ing and reproducingmeans.

It is well-known to so dispose these electro magnets that such wire ortape shall be moved between two or more of them, and further to soarrange the electromagnets that the cores on one side of the wire ortape are offset with respect to those on the opposite side thereof, thatis to say, not in line with them. In accordance with -the distancebetween adiacent cores either the higher or the lower frequencies willpredominate.

The invention is concerned with a construction that shall enable thisdistance to be varied.

One embodiment of the invention is described hereafter by way ofexample, reference being had to the accompanying drawing in which Fig. 1is an elevationof the talking head partly in section, Fig. 2 anelevation thereof as viewed from the side opposite to that representedin Fig. 1, Fig. 3 is a partially sectioned end elevation, the sectionbeing on the line A-B of Fig. 2, Fig. 4 is a similar view to Fig. 3, thesection being on the line C-D of Fig. 2. Fig. 5 on a larger scale thanFigs. 1 to 4 shows a section on the lin EF of Fig. 2.

The talking head has two blocks I, 2 in which electromagnets 3, 4 aredisposed the cores of which are represented in dotted lines. Thesemagnets are to coact in awell-known manner with a steel wire thatextends along a channel 8 formed by the blocks l, 2 which thusconstitute a casing for the wire. The wire is not shown.

Fixed to the block I are two bearings 9, ill in which a spindle 5 isrotatably mounted. This, spindle has a head 6 that may,be-milled orserrated as indicated in Figs. 1 and 2, and also has a screw-thread IIfor engagement with a female thread of a bushing l2 secured to block 2.

Spindle 5 and block I are prevented from moving longitudinally of eachother. This may be done for instance by one of the bearings 9, III, inthe case represented bearing iii, projecting into an annular groove I3of the spindle, as will best be seen from Fig; 5.

Thus, by turning the spindle by means of head 6, block 2 is displaced'along block I in one or the other direction according to the directionin which the spindle is rotated. As a result the distance between thecores of the magnets 3, 4 is varied so that either the higher or thelower frequencles can be made to preponderate. This is recording orreproducing speech in the first place and then musical performances.

The novel arrangement enables thisvariation of distance to be effectedeven during the operation of the device, without any parts having to beinterchanged, so that it is at anytime possible to cause the higherfrequencies to be in preponderance of the lower ones, or vice versa.

In order also to enable the amount of variation to be ascertained, avernier or like gradua tion I may be provided on the blocks I, 2, asshown in Fig. 1. A vernier graduation is used by preference, since thedistances between the adjacent cores are very small and since also thedisplacement of these cores should be very small.

What is claimed is:

1. In an electromagnetic talking head for use with ferrous recordbearing filaments, guides to position such a filament, a-palr ofelectromagnets arranged to be on different sides of such a advantageousin several respects, such as when 1 filament when it is so positioned,the axes of said electromagnets being mutually offset, means forvariably supporting said magnets so that theextent of said offset may beadjusted, and graduated indicating means adapted to indicate the extentof said oflset.

2. In a talking head, a casing made in two parts forming a channeladapted to guide a sound record carrier, and electromagnetic means ineach of these parts, these electromagnetic means being arranged onopposite sides of said channel and offset with respect to each other,the said two parts of the casing being displaceable with respect to eachother for varying the distance between the cores of the saidelectromagnetic means, the said two parts of the casing being providedwith a series of graduations and a on.-

operating indicating means adapted to indicate' the amount of theirmutual displacement.

3. In a talking head, a. casing made in two parts forming a channeladapted to guide a sound record carrier, and electromagnetic means ineach of these parts, these electromagnetic means being arranged onopposit sldes-of said channel and offset with respect to each other, thesaid two'parts'of the casing being displaceable with respect, toeach-other for varying the distance between the cores of the saidelectromagnetic means, the said two parts of the casing being providedwith a series of graduations and a cooperating series of verniergraduations adapted to indicate the amount of their mutual displacement.

SEMI BEGUN.

